The present invention relates to ladders used in marine applications. In particular, the invention relates to aquatic ladders used as boarding ladders on boats or to climb onto floating or fixed docks.
As used herein the term “aquatic ladder” is intended to mean those ladders which are specifically designed and intended for use while partially submerged. In the past, the primary objective addressed in the design of aquatic ladders has been ease of storage, rather than ease of use. Thus, many ladders designed for marine and aquatic applications (e.g., as boarding ladders on boats and ladders used to climb onto both fixed and floating docks) have been short (e.g., they had relatively few rungs extending into the water), or they have included features which allow them to be compact for storage and expanded for use (e.g., hinges for folding, sliding extensions, or sides made of chain or rope, so that they could be stored in a small volume). Most such aquatic ladders have also included rungs which are rather narrow, or round, making them even more uncomfortable and difficult to use. Due to their construction, the aquatic ladders of the prior art were also prone to considerable movement, as one tried to climb them, and they often lacked a secure handhold, particularly above the water level. While storage space is limited, and is, therefore, acknowledged to be a problem on boats, the consequence of making storage the primary objective in the design of an aquatic ladder is that the aquatic ladders heretofore known were difficult to use, and a challenge to ascend, particularly by pets (such as dogs), elderly persons, those carrying aquatic gear, such as SCUBA equipment or water skis, possibly some disabled persons, and even those in good physical shape who were simply tired from having engaged in aquatic activities without some assistance.
Further problems with the aquatic ladders previously known have involved the manner in which they attached to the boat or dock. In particular, since compact size has been the issue which was generally addressed, many ladders designed for aquatic use simply reached up to the lowest point possible, e.g., the surface of the dock or the gunwale (or swim platform) of the boat to be boarded. Further, they were typically placed immediately next to the object to which they were attached, meaning that they had very narrow steps, and that they were prone to swinging under such objects as they bore the weight of a person climbing them. Such designs have further increased the difficulty of their use.
While some of the aquatic ladders heretofore known have included design features which increase their usability, none have been found which truly address the issue of ease of use in a marine environment. By way of example, ladders heretofore known include those described in U.S. Pat. No. 6,378,654 entitled LADDER PIVOTALLY ATTACHED TO A GENERALLY VERTICALLY EXTENDING SURFACE which issued on Apr. 30, 2002 to Ziaylek, Jr., et al. which describes a ladder designed to be attached to a vehicle having a generally vertical wall. As shown in FIGS. 1-5, the ladder has a step supporting portion which slopes away from the vertical wall which supports substantially horizontal steps.
U.S. Pat. No. 5,896,946 entitled BOARDING LADDER AND WINCH MOUNT FOR BOAT TRAILERS AND THE LIKE which issued on Apr. 27, 1999 to W. E. Brackett describes a ladder having “steps” which enable easy access to a boat. However, while the ladder includes steps, and while it is adapted for use with a boat, it is intended to be integrated into a winch assembly on a boat trailer, and it is intended for use in accessing the boat while the boat is on a trailer, rather than for in-water use. Further, the disclosure of that patent distinguishes the ladder of the patent from a ladder which would provide in-water access in that it distinguishes the ladder of the patent from “boarding ladders”(See, Col. 1, lines 23-30) or aquatic ladders of the type described herein.
U.S. Pat. No. 5,339,919 entitled BOARDING LADDER ASSEMBLY HAVING A VARIABLE COUNTERWEIGHT LIFTING FORCE which issued on Aug. 23, 1994 to J. W. Boyd describes a boarding ladder assembly for mounting a boarding ladder in a manner which allows the boarding ladder to be lowered and raised. Again, the ladder is used on a vehicle, but it is not intended for a marine application in which the steps would be under water.
U.S. Pat. No. 4,724,925 entitled BOAT BOARDING LADDERS which issued on Feb. 16, 1988 to R. G. Ritten describes a boat boarding ladder having horizontal steps which are attached to a section which extends into the water at an angle from the vertical.
U.S. Pat. No. 4,719,989 entitled BOAT BOARDING LADDERS HAVING A STOWAGE FEATURE which issued on Jan. 19, 1988 to R. G. Ritten describes a boat boarding ladder having an upper inverted “U” shaped railing, but it does not have a vertical member, nor does it have hinges at the point of attachment.
U.S. Pat. No. 4,243,120 entitled RETRACTABLE BOARDING LADDER which issued on Jan. 6, 1981 to D. Pratt, Jr. describes a “boarding stairway” which has a stair supporting member which extends away from the vertical and which supports substantially horizontal steps. The entire assembly is adapted to be moved vertically, but it is not adapted for a marine application, nor does it include a vertical member which extends downward from the upper portion or an inverted “U” railing at its upper portion.
U.S. Pat. No. 4,186,820 entitled BOARDING LADDER AND STRAPS which issued on Feb. 5, 1980 to D. Cosman et al. describes a boarding ladder for use with an inflatable boat. The rungs are supported by a member which extends down and away from the boat. However, the ladder does not include the vertical member, the inverted “U” shaped rail, or the wide, horizontal steps of your invention.
U.S. Pat. No. D-411,049 entitled ROLLING STAIR which issued on Jun. 15, 1999 to C. G. Curtis illustrates a ladder-like apparatus having stair-like steps which attach to a vertical rear portion which extends downward to the lowest vertical step. Also, the rolling stairs, appear to include wheels which allow them to roll on surface.
U.S. Pat. No. D-243,953 entitled SAFETY LADDER FOR THE ABOVE GROUND POOL which issued on Apr. 5, 1977 to P. F. Gannon illustrates a ladder having two sets of steps. While this ladder appears to be intended for use in an above-ground pool, as shown in FIG. 3 thereof, the teaching is to place the vertically oriented rungs, rather than the step-like stairs into the water. Further, this ladder includes a rear vertical portion (shown in the water in FIG. 3) which extends downward to the lowest vertical step on the sloped portion.
U.S. Pat. No. 3,446,309 entitled ROLLER MOUNT FOR LADDERS which issued on May 27, 1969 to R. D. Davis et al. describes a way to mount casters on the bottoms of the legs of folding ladder.
U.S. Pat. No. 3,283,402 entitled METHODS FOR FABRICATING LIGHTWEIGHT METAL LADDER which issued on Nov. 8, 1966 to C. E. Larson describes methods for forming ladders with lightweight metal rungs.